The grayling or rock grayling (Hipparchia semele) is a species in the brush-footed butterfly family Nymphalidae. The grayling is not found in west France, large parts of Greece, Albania, North Macedonia, and south of Bulgaria and the Mediterranean islands.

Habitat

Grayling populations are typically found in dry habitats with warm climates to aid in their thermoregulatory behavior. They tend to feed on the following plants:

Life history

Life cycle

Note that information on this species applies to Great Britain and some details may not be consistent with the species in other parts of its range.

There is one generation per year. The eggs are laid from July to September singly, often on the food plant. H. semele eggs are white at first, but turn pale yellow as they develop. The egg stage generally lasts between two and three weeks.

Protective coloration and behavior

Cryptic and mimicking color and behavior

thumb|Grayling butterfly engages in cryptic coloring behavior to camouflage into environment.

Hipparchia semele engages in cryptic coloring, or camouflage that makes it difficult to see them when they are resting on the bare ground, tree trunks, rocks, etc.

Mating

Mate searching behavior

When it comes time to mate, male and female H. semele meet above a solitary tree in a wide and open area. This takes on many forms, from a tall tree in a heathland to bare patches of ground in sand dunes. The female lays her eggs on various fine-leaved grasses, including fescues, bents, and bromes, a few centimeters above the ground.

Displaying

Male graylings make short and frequent flights, both spontaneous and non-spontaneous. These may function as a signal of display for females.

Physiology

Flight

The grayling is a large and distinctive butterfly when in flight. The flight of a grayling is characterized by strong loops.

The male tends to orient its body and wings to control which parts of the body are exposed to the sun. This allows the grayling to keep its body temperature as close to the preferred level as possible. Therefore, at lower temperatures, the male grayling exposes as much of its body area as it can to increase the surface area facing the sun. This process is sometimes called sun-basking. This can raise body temperatures by up to 3 degrees Celsius. Contrarily, at high temperatures, the male grayling exposes as little of its body area as possible to the sun. This process can lower body temperatures by up to 2.5 degrees Celsius. At intermediate temperatures, the male grayling is often observed gradually changing his body orientation and posture in order to evenly spread the heat all over his body. This behavior can often be observed by male butterflies defending their territories.

It is now a UK Biodiversity Action Plan species (Butterfly Conservation, 2007).

Habitat loss

Much of the Hipparchia semele<nowiki />'s common habitats, such as heathlands, have started to become transformed into agricultural land. The dry habitats are occupied by trees and other greenery, reducing the optimal available habitats for the graylings.

References

  • Butterfly Conservation website
  • UK Butterflies website – includes a list of sites around the UK where this species can be found.